Condenser

ABSTRACT

A condenser includes a cooling section having a plurality of vapor passages to convert vapor into water, a blower for drawing water produced in the vapor passages out of the vapor passages, and a recovery section for receiving the drawn-out water. Thus, the water produced in the vapor passages in the cooling section can be prevented from occluding the vapor passages.

FIELD OF THE INVENTION

[0001] The present invention relates to a condenser for converting anoperating medium in a gas-phase state into a liquid-phase state.

BACKGROUND ART

[0002] There is such a conventionally known condenser including acooling section in which a large number of narrow passages for coolingmedium such as air and a large number of narrow vapor passages aredisposed alternately.

[0003] If the vapor passages are narrow, however, there is a possibilitythat the following disadvantage may be encountered: the operating mediumin the liquid-phase state produced in such passages, e.g., wateroccludes the passages due to factors such as a surface tension of theoperating medium and as a result, the amount of water vapor flowing inthe cooling section is reduced, resulting in a reduction in condensingperformance.

DISCLOSURE OF THE INVENTION

[0004] It is an object of the present invention to provide a condenserof the above-described type, wherein the operating medium in theliquid-phase state produced in the passages in the cooling section canbe prevented from occluding the passages.

[0005] To achieve the above-described object, according to the presentinvention, there is provided a condenser comprising a cooling sectionhaving a plurality of operating medium passages to convert an operatingmedium in a gas-phase state into a liquid-phase state, a suction meansfor drawing the operating medium in the liquid-phase state produced inthe operating medium passages out of the passages, and a recoverysection for receiving the operating medium drawn out in the liquid-phasestate.

[0006] With the above arrangement, the operating medium in theliquid-phase state can be forcibly discharged out of the passages andhence, the amount of operating medium flowing in the gas-phase state inthe cooling section can be maintained, whereby the intrinsic condensingperformance can be ensured.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is an illustration for explaining a Ranking cycle system;

[0008]FIG. 2 is a vertical sectional front view of a condenser;

[0009]FIG. 3 is an enlarged view of essential portions of FIG. 2;

[0010]FIG. 4 is a view for explaining one example of a structure of acooling section and a recovery section, and corresponds to a sectionalview taken along a line 4-4 in FIG. 5;

[0011]FIG. 5 is a sectional view taken along a line 5-5 in FIG. 2 andcorresponds to a sectional view taken along a line 5-5 in FIG. 4;

[0012]FIG. 6 is a sectional view showing an annular panel in a state inwhich a portion thereof has been fitted in a groove in a guide tube;

[0013]FIG. 7 is a sectional view showing the annular panel in a state inwhich a portion protruding into the guide tube has been cut away;

[0014]FIG. 8 is a view taken in the direction of an arrow 8 in FIG. 7;

[0015]FIG. 9 is a sectional view taken along a line 9-9 in FIG. 2 andcorresponds to a sectional view taken along a line 9-9 in FIG. 4;

[0016]FIG. 10 is a sectional view taken along a line 10-10 in FIG. 2;

[0017]FIG. 11 is a developed view of a cam groove;

[0018]FIG. 12 is a sectional view of essential portions of an anotherexample of a cooling section; and

[0019]FIG. 13 is a view showing another example of a structure of acooling section and a recovery section.

BEST MODE FOR CARRYING OUT THE INVENTION

[0020] A Rankine cycle system R shown in FIG. 1 includes an evaporator 2for generating a high-pressure water vapor (an operating medium in thegas-phase state) having a raised temperature, namely, a high-temperatureand high-pressure vapor, from a high-pressure liquid, e.g., water (anoperating medium in the liquid-phase state) using an exhaust gas from aninternal combustion engine 1, an expander 3 for generating an output bythe expansion of the high-temperature and high-pressure vapor, acondenser 4 for liquefying the vapor dropped in temperature and pressureby the expansion, namely, a dropped-temperature and dropped-pressurevapor discharged from the expander 3, thereby producing water, and afeed pump 5 for supplying water from the condenser 4 to the evaporator 2under a pressure.

[0021] Referring to FIG. 2, the expander 3 includes a substantiallyhorizontal high-temperature and high-pressure vapor introducing pipe 7at a center portion of one end of a casing 6 of the expander 3, and aplurality of dropped-temperature and dropped-pressure vapor outlet bores8 in an upper portion of the other end of the casing 6. In addition, theexpander 3 includes a substantially horizontal output shaft 9 at acenter portion thereof. The condenser 4 is mounted to the expander 3, sothat it receives the dropped-temperature and dropped-pressure vapor fromeach of the outlet bores 8.

[0022] The condenser 4 includes a cylindrical housing 10, and a coolingsection 12 provided within a larger-diameter tubular portion 11 of thehousing 10 for converting the dropped-temperature and dropped-pressurevapor into water. The cooling section 12 is formed into a hollowcolumnar shape with a plurality of annular panel 13 made of a metalmaterial such as a stainless steel, aluminum and the like and superposedone on another, and is provided at its center portion with a vaporintroducing bore 15 provided by the bores 14 in the annular panels 13.The centerline of the vapor introducing bore 15 is in accord with anaxis of the output shaft 9.

[0023] An annular end plate 17 existing at one end of a tubular vaporguide 16 and a flange 18 existing around an outer periphery of the endplate 17 are opposed to an annular end face of the cooling section 12 onthe side of the expander 3. An outer peripheral portion of the flange 18is integral with the cooling section 12. A bore 19 in the end plate 17is in accord with the vapor introducing bore 15. A flange 20 existing atthe other end of the tubular vapor guide 16 is superposed on a flange 21existing at one end of the larger-diameter tubular portion 11, and issecured to a flange 23 of the expander 3 by a plurality of bolts 22.Thus, the dropped-temperature and dropped-pressure vapor outlet bores 8in the expander 3 face into the tubular vapor guide 16.

[0024] The housing 10 has a split smaller-diameter tubular portion 24disposed at the other end of the larger-diameter tubular portion 11. Aflange 25 of the smaller-diameter tubular portion 24 is opposed to anannular end face of the cooling section 12, and an outer periphery ofthe smaller-diameter tubular portion 24 is integral with the coolingsection 12.

[0025] A transmitting shaft 27 is mounted to the output shaft 9 of theexpander 3 through a spline-coupling portion 26. The transmitting shaft27 protrudes to the outside through the vapor introducing bore 15 in thecooling section 12 and an end wall 28 of the smaller-diameter tubularportion 24, and is rotatably supported at the end wall 28 with a bearing29 interposed therebetween. Two seal rings 31 are mounted to thetransmitting shaft 27 for sealing the transmitting shaft 27 and a shaftinsertion bore 30 provided in the end wall 28 outside the bearing 29from each other.

[0026] Referring also to FIGS. 3 and 4, the following tubes are disposedin a lower portion of the housing 10: a stationary guide tube 32extending in parallel to the transmitting shaft 27, and a recovery tube33 which is slidably fitted in the guide tube 32 and serves as arecovery section for recovering water produced by cooling thedropped-temperature and dropped-pressure vapor. An end of the recoverytube 33 adjacent the expander 3 is closed, but an opposite end of therecovery tube 33 is open. A recovery tube detent means comprising a key34 and a key groove 35 is provided between an inner peripheral surfaceof the guide tube 32 and an outer peripheral surface of the recoverytube 33.

[0027] As shown in FIGS. 4 and 5, each of the annular panels 13 in thecooling section 12 includes a group of projections 36 formed bypressing, and a plurality of tube-shaped vapor passages(operating-medium passages) 37 are defined between a set of the twoannular panels 13 by brazing the opposed groups of projections 36 onsuch set of the two annular panels 13 to each other. The peripheries ofthe bores 14 in such two annular panels 13 are sealed by brazing of twoarcuate projections 38 with their upper portions opened, and an inlet 39of the vapor passage 37 is defined between opposite ends of the arcuateprojections 38 to communicate with an upper portion of the vaporintroducing bore 15. Substantially entire outer peripheries of the twoannular panels 13 are sealed using a combination of the hemming and thebrazing, but hemmed portions 41 are separated at a lower portion and ata notch 40 located on a diameter bisecting the inlet 39. A peripheralportion 42 of the notch 40 is fitted into and brazed in one of aplurality of grooves 43 provided at predetermined distances in an axialdirection of the guide tube 32. Thus, an inner peripheral surface of thenotch 40 is matched to an inner peripheral surface of the guide tube 32,whereby outlets 44 of the vapor passages 37 defined by the annularpanels 13 face into the guide tube 32.

[0028] At the end of the cooling section 12 adjacent the expander 3, thevapor passage 37 is defined by cooperation of the one annular panel 13and the annular end plate 17 as well as the flange 18, and at the endadjacent the smaller-diameter tubular portion 24, the vapor passage 37is defined by cooperation of the one annular panel 13 and the flange 25as well as a partition wall 45 on an inner peripheral side of the flange25. Each of the hemmed portions 41 is fitted into corresponding one ofgrooves 47 in the comb-shaped distance-adjusting plate 46 extending in adirection of a generating line of the cooling section 12 (also see FIG.12). A plurality of the distance-adjusting plates 46 are disposed atpredetermined distances in a circumferential direction of the coolingsection 12.

[0029] As shown in FIG. 5, the vapor passages 37 comprise a singlerising passage 48 extending upwards on a panel radius from the inlet 39,a plurality of branch passages 49 diverted in opposite directions fromthe rising passage 48 and in a circumferential direction, a plurality ofdowncomer passages 50 leading to lower portions of the branch passages49, a plurality of convergent passages 51 leading to lower portions ofthe downcomer passages 50, and the outlets 44 where the convergentpassages 51 are collected together.

[0030] To define the outlets 44 of the vapor passages 37, as shown inFIG. 6, portions of the annular panels 13 hemmed over their entire outerperipheral portions, which are on the side of the convergent passages51, are fitted into the grooves 43 in the guide tube 32, so that aportion of each of the hemmed portions and a portion in the vicinitythereof protrude into the guide tubes 32. Then, the annular panels 13are brazed to inner surfaces of the grooves 43 in the guide tube 32.Thereafter, portions 52 of the annular panels 13, which protrude intothe guide tube 32, are cut away and as a result, the notch 40 isdefined, and the outlets 44 open into the notch 40.

[0031] In this case, as shown in FIG. 8, each of the grooves 43 includesa wider portion 43 a fitted to the two annular panels B, and a narrowerportion 43 b which opens into the a bottom surface of the wider portion43 a and is fitted to the hemmed portion 41. Thus, it is possible toreliably seal the peripheries of the outlets 44 and to increase thestrength of bonding between each of the panels 13 and the guide tube 32.

[0032] As shown in FIGS. 4 and 9, each of cooling air passages 54 ascooling medium passages is defined between the adjacent vapor passages37, namely, is a gap between the two annular panes 13 defining each ofthe vapor passage 54 and opposed to each other. In order to ensure theair passages 54, the two annular panels 13 are provided with pluralitiesof small projections 55 mated with each other. Inlets 56 of the airpassages 54 are defined by a tube portion 58 existing at a lower bulge57 of the larger-diameter tubular portion 11 of the housing 10, and onthe other hand, outlets 59 of the air passages 54 are located betweenthe adjacent hemmed portions 41 at upper portions of the annular panels13 defining the vapor passages 37. In the two annular panels 13 definingthe air passage 54, inner peripheral edges of the bores 14 therein arebonded to each other by the combination of the hemming and the brazing,and the entering of a cooling air flow into the vapor passages 37 andthe leakage of the vapor into the air passages 54 are prevented by asealing effect provided by such hemmed portions 60. The larger-diametertubular portion 11 is provided at its upper portion with an exhaust hood61 covering the outlets 59. On the outer peripheral surface of thecooling section 12, the exhaust hood 61 and the lower bulge 57 aresealed from each other by a pair of side panels 62.

[0033] When the outer peripheral portions of the adjacent annular panels13 defining the vapor passage 37 are bonded by the combination of thehemming and the brazing, as described above, the spreading between bothof the outer peripheral portions can be prevented to provide a decreasein air resistance, thereby reducing a loss in pressure in the condenser4.

[0034] A coefficient of condensation heat transfer of the vapor is farlarger than a coefficient of convection heat transfer of air and hence,in order to provide the compactness of the cooling section 12, it isrequired that the heat resistances on a cooling surface of each of thevapor passage 37 and a cooling surface of each of the air passages 54 beequalized to each other by decreasing the area of the cooling surface ofthe vapor passage 37 and increasing the area of the cooling surface ofthe air passage 54. Therefore, the groups of projections 36 on theadjacent panels 13 are bonded to each other to define the vapor passages37 independently into tube shapes. On the other hand, the air passages54 are defined by maintaining the distances between the adjacent panels13 constant to provide a structure in which the opposed panels 13 arenot in contact with each other, and the area of the cooling surface ofeach of the air passages 54 is larger than that of the cooling surfaceof each of the vapor passages 37.

[0035] As clearly shown in FIGS. 2 and 3, when the outlets 44 of thevapor passages 37 are classified into a plurality of groups eachcomprising the same number of outlets 44, a plurality of the outlets 44in each of the groups intermittently communicate with one of a pluralityof circumferentially extending slot-shaped communication bores 63defined at equal distances in an axial direction in a larger-diametertubular portion 53 of the recovery tube 33.

[0036] As shown in FIGS. 2, 3 and 10, a blower 64 is disposed within thesmaller-diameter tubular portion 24 of the housing 10, and serves as asuction means for forcibly drawing water produced in the vapor passages37 out of the vapor passages 37 via the outlets 44 and the communicationbores 63.

[0037] The blower 64 comprises a cylindrical casing 65 having acenterline c at a location displaced by ε from an axis a of thetransmitting shaft 27, a rotor 67 accommodate in the casing 65 andmounted to the transmitting shaft 27 through a spline coupling 66, and aplurality of vanes 69 slidably fitted into a plurality of radial grooves68 in the rotor 67. The casing 65 comprises a cylindrical body 70, and alid 71 attachable and detachable to and from the body 70. The body 70 ismounted to an end wall 73 of a central tubular portion 72 existing onthe partition wall 45 by a plurality of bolts 74.

[0038] A suction port 75 is provided in a lower portion of the casing 65and communicates with the larger-diameter tubular portion 53 of therecovery tube 33 via a conduit 76 provided in the guide tube 32, atubular space 78 between the inner peripheral surface of the guide tube32 and an outer peripheral surface of a smaller-diameter tubular portion77 integral with the larger-diameter tubular portion 53 of the recoverytube 33, a plurality of through-bores 79 provided in thesmaller-diameter tubular portion 77 and the inside of thesmaller-diameter tubular portion 77. On the other hand, a discharge port80 is provided in an upper portion of the casing 65 and communicates thevapor introducing hole 15 in the cooling section 12 through the insideof the smaller-diameter tubular portion 24 and a through-bore 82 definedin a peripheral wall region 81 on the central tubular portion 72 of thepartition wall 45.

[0039] A bore 83 permitting the reciprocal movement of thesmaller-diameter tubular portion 77 is defined in a lower portion of theend wall 28 of the smaller-diameter tubular portion 24, and a water tank84 formed by components such as the end wall 28, the guide tube 32 andthe like is disposed to surround the bore 83. The inside of thesmaller-diameter tubular portion 77 of the recovery tube 33 communicateswith an inlet 85 a of the water tank 84 defined in the peripheral wallof the guide tube 32 through the through-bore 79 and the tubular space78, and an outlet 85 b in the water tank 84 communicates with a suctionport of the feed pump 5.

[0040] To put each of the communication bores 63 provided in thelarger-diameter tubular portion 53 of the recovery tube 33 sequentiallyinto communication with the outlets 44 of the vapor passages 37, a drivemechanism for reciprocally moving the larger-diameter tubular portion 53of the recovery tube 33 within the guide tube 32 is provided in thefollowing manner.

[0041] A boss 87 is provided at a central portion of the rotor 67 in theblower 64 to protrude from a central bore 86 in the lid 71, and alarger-diameter gear 88 is mounted to the boss 87 through a splinecoupling 89. A gear retaining tube 90 is rotatably fitted over thesmaller-diameter tubular portion 77 of the recovery tube 33, and asmaller-diameter gear 93 is mounted to the gear retaining tube 90between a pair of flange-shaped portions 91 of the gear retaining tube90 through a spline coupling 92 and is meshed with the larger-diametergear 88. The flange-shaped portions 91 are supported between an end faceof the guide tube 32 and an end face of an annular protrusion 94 on aninner surface of a lower portion of the end wall 28. A cam groove 95 isdefined in an outer peripheral surface of the smaller-diameter tubularportion 77, as clearly shown in FIG. 11 in a developed manner, and a pin96 engaged in the cam groove 95 is supported in a groove 97 axiallydefined in an inner peripheral surface of the gear-retaining tube 90. Adistance between chevron portions 98 of the cam groove 95 corresponds toa stroke of the recovery tube 33, and one of the communication bore 63is sequentially put into communication with the plurality of outlets 44existing in a range of such stroke, namely, in one group.

[0042] In the above-described arrangement, when the output shaft 9 isrotated by the operation of the expander 3, the blower 64 is operatedthrough the transmitting shaft 27, and the larger-diameter gear 88 isrotated. The smaller-diameter gear 93 is also rotated by the rotation ofthe larger-diameter gear 88 and hence, the recovery tube 33 isreciprocally moved through the pin 96 and the cam groove 95, whereby theplurality of outlets 44 in the vapor passages 37 in each group areintermittently put into communication with the inside of the recoverytube 33 through the communication bores 63 in the recovery tube 33, anda suction force is applied to each of the outlets 44.

[0043] The dropped-temperature and dropped-pressure vapor dischargedfrom each of the outlet bores 8 in the expander 3 flows via the insideof the tubular vapor guide 16 into the vapor introducing bores 15 in thecooling section 12 and then enters into each of the vapor passages 37through the inlet 39. The dropped-temperature and dropped-pressure vaporis then passed via the rising passage 48 and the plurality of branchpassages 49 in each of the vapor passages 37 into the plurality ofdowncomer passages 50, where such vapor is cooled by the cooling airflowing through the plurality of air passages 54 to produce water. Thewater is forcibly drawn out of the outlets 44 in the vapor passages 37by the suction force of the blower 64 and accumulated in thelarger-diameter tubular portion 53 of the recovery tube 33 via thecommunication bores 63. When the amount of water accumulated in thelarger-diameter tubular portion 53 exceeds a defined amount, the waterflows via the smaller-diameter tubular portion 77 as well as thethrough-bore 79 therein and the tubular space 78 and enters into thewater tank 84 through the inlet 85 a.

[0044] When the water produced in each of the vapor passages 37 isforcibly discharged therefrom, the amount of dropped-temperature anddropped-pressure vapor flowing in the cooling section 12 can bemaintained, whereby a desired condensation performance can be ensured.

[0045] When uncondensed vapor is produced, such vapor is separated fromthe water by a gas-liquid separating effect provided by the space withinthe larger-diameter tubular portion 53 of the recovery tube 33 and isthen drawn via the smaller-diameter tubular portion 77, the through-bore79 in the smaller-diameter tubular portion 77, the tubular space 78 andthe conduit 76 and through the suction port 75 into the blower 64 by thesuction force of the blower 64. Then, such uncondensed vapor is passedfrom the discharge port 80 via the inside of the smaller-diametertubular portion 24 and the through-bore 82 in the partition wall 45 intothe vapor introducing bore 15 in the cooling section 12 by the feedingaction of the vanes 69 of the blower 64 and then returned again into thevapor passages 37, where the uncondensed vapor is liquefied. Thus, it ispossible to avoid a decrease in amount of water as the operating mediumin the Rankine cycle system R to ensure a required amount of water.

[0046] If each of the panels 13 is formed of an aluminum-based material(including pure aluminum and an aluminum alloy) in consideration of theheat conductivity, the surface treatment property, the reduction inweight, the recycling property and the like of the cooling section 12,hydrogen which is a non-condensed gas is produced by a chemical reactionbetween the dropped-temperature and dropped-pressure vapor, namely, thewater vapor and the aluminum-based material, and most of the hydrogen isdischarged to the outside of the vapor passages 37 by the water, butthere is a possibility that a portion of the discharged hydrogen may beresident within the narrow vapor passages 37 and as a result, thecooling effect for the dropped-temperature and dropped-pressure vapormay be obstructed by the resident hydrogen. In the present embodiment,however, if hydrogen is produced, then such hydrogen can be circulatedin a path comprising the cooling section 12, the recovery tube 33, theblower 64 and the cooling section 12 and thus prevented from beingresident within the vapor passages 37.

[0047] In addition, even if the distance between the adjacent panels 13in the cooling section 12 is decreased to the utmost, the residence ofthe water can be avoided by forcibly discharging the water from thevapor passages 37. Thus, it is possible to provide a reduction in sizeof the cooling section 12 and to enhance the mountabitity of thecondenser 4 in the Rankine cycle system R for the vehicle.

[0048] Further, the outlets 44 in the plurality of vapor passages 37 ineach group and each of the communication bores 63 of the recovery tubes33 are intermittently put into communication with each other, and hence,even if a blower of a lower capacity is used as the blower 64, a largesuction force can be applied to each of the outlets 63, therebyproviding an energy-saving. The energy-saving is particularly effective,because an output from the expander 3 is utilized as a power source forthe blower 64.

[0049] Yet further, the cylindrical cooling section 12 and the blower 64are accommodated in a projected plane of the flange 23 of the expander3, and the dropped-temperature and dropped-pressure vapor introducingbore 15 in the cooling section 12 is provided around the centerline ofthe projected plane and hence, it is possible to provide the compactnessof an assembly comprising the expander 3 and the condenser 4 providedwith the blower 64.

[0050]FIG. 12 shows another example of the cooling section 12. In thisexample, in a state in which a distance-adjusting leaf spring 99 hasbeen interposed between the adjacent panels 13 defining the air passage54, a laminate comprising the panels 13 and the leaf springs 99 isplaced on a preselected jig, and the hemmed portions 41 and the matedgroups of projections 36 are brazed.

[0051] Thus, the hemmed portions 41 and the opposed projections 36 incontact with each other by the repulsing force of the leaf springs 99can be bonded reliably, whereby the strength and reliability of thebonding can be enhanced, and the distance between the air passages 54can be maintained at a predetermined value. In this case, if two brazingmaterials placed at portions to be hemmed prior to the hemming areclamped between opposed inner surfaces of a U-shaped portion u producedby the hemming and opposite surfaces of a flat plate-shaped portion plocated between such opposed inner surfaces, respectively, the operationfor brazing each of the hemmed portions 41 can be facilitated, and thebonding strength can be increased. This also applies to each of thehemmed portions 60.

[0052] In this example, two types of the annular panels 13 are used,which have groups of projections 36 disposed at different locations, sothat the branch passages 49 in the adjacent vapor passages 37 aredisposed in a zigzag manner. The entire structure of the cooling section12 constructed using such annular panels 13 is as shown in FIG. 13.

What is claimed is
 1. A condenser comprising a cooling section (12)having a plurality of operating medium passages (37) to convert anoperating medium in a gas-phase state into a liquid-phase state, asuction means (64) for drawing the operating medium in the liquid-phasestate produced in said operating medium passages (37) out of saidpassages (37), and a recovery section (33) for receiving said operatingmedium drawn out in the liquid-phase state.
 2. A condenser according toclaim 1, wherein a suction side of the suction means (64) communicateswith outlets (44) of said operating medium passages (37), and adischarge side of the suction means (64) communicates with inlets (39)of said operating medium passages (37).